Pilot - The Effect of Parity Legislation on Substance Abuse Treatment Parity coverage for substance abuse treatment services has been debated recently at both the state and federal levels of government. Traditionally, insurance coverage for treatment of addictive disorders has been strictly limited under private insurance and even many Medicaid programs. Objections to parity of coverage for substance abuse services at the same level as medical services typically focus on the cost of the policy. Recently the U.S. Congress has considered legislation that would mandate "parity" for coverage of substance abuse care under private health insurance. Cost has been a central issue. The State of California implemented its mental health parity legislation in July of 2000. That law does not address coverage for substance abuse treatment. In January of 2001, the FEBHP implemented parity for both mental health and substance abuse services within a managed care network or for all indemnity benefits. Beginning in January 2001, the California experience offers us the opportunity to study the incremental impact of adding a parity benefit for substance abuse treatment to private health insurance. This pilot represents a collaboration between the Brandeis-Harvard Center and United Behavioral Healthcare (UBH), a large national managed behavioral health care carve-out vendor that is a subsidiary of the United Health Care Group. UBH manages mental health and substance abuse services for Blue Shield of Northern California. The specific aims of this pilot research are: (1) To examine the impact of parity for substance abuse treatment on the in-network cost of health care, substance abuse care and mental health care; (2) To examine the impacts on in-network patterns of substance abuse and mental health treatment of implementing parity for mental health services but not substance abuse care; and (3) To estimate the impact of parity for substance abuse treatment on indicators of the quality of substance abuse treatment.